The Shop > Tools
Sieg Super C3 bearing change
John Rudd:
--- Quote from: loply on January 21, 2012, 01:22:54 PM ---John,
I'm interested in your comments about the taper bearings requiring a sliding fit. I fitted the same to mine many moons ago and this never occurred to me, I just pressed them on using a screw press of some kind. I wonder if I should re-do this.
Cheers,
Rich
--- End quote ---
Rich,
Fitting taper bearings takes me back to the time when I used to 'do' cars....
Typically Fords had taper rollers on the front...I remember overtightening one to the point that after a few miles it got all hot and bothered and broke up...I didnt realise this at the time until I arrived at my folks house..attempts at removing the inner race( even with oxy-acetylene) were futile as it had welded itself to the stub axle...a new s.a was needed to get me home( courtesy of the local breakers yard)...
Besides, if the inner race isnt allowed to float on the shaft how does one adjust the end float with a spanner?.... Oh, I know, an even bigger spanner.. :coffee:
I applied the same thought process when I changed the bearings on my Chester minimill, which happen to be the same ball bearing races as the minilathe.....
WillieL:
John,
That is an outstanding job that is well documented. :thumbup: :thumbup: :thumbup:
Regarding the fit of the bearings I could not agree more having 'done' cars for a living for a lot of years. The chuck end of the spindle could be a press fit (I would recommend it actually) but as you stated the 'tail end' bearing needs to be able to slide a bit in order to properly set the bearing pre-load. And the finial setting should be done after the lathe has been run awhile, and the bearings are up to normal running temperature.
Do you by chance remember the bearing numbers you used? Any problems with grease leaking out of the housing?
I've added a ball bearing to the cross slide on my little 7x10 which made things much smoother, but I really like the idea of using the tapered bearings in the headstock. I have a 4" chuck on mine which is quite hefty for it's size, and I think this mod would be a good move for me.
Thank you for sharing all the info. :beer:
John Rudd:
--- Quote from: WillieL on January 26, 2012, 07:57:37 AM ---
Do you by chance remember the bearing numbers you used? Any problems with grease leaking out of the housing?
--- End quote ---
The bearings are available from ArcEurotrade part number 30206...Although admittedly I didnt buy mine from there...Any reputable bearing supplier should be able to provide them, but it pays to shop around..There's a big difference in price and quality...The bearings Arc supply are quality items, as are brands like SKF or FAG.
As for grease loss, none should come out of the housing unless they have been overpacked :coffee:
I added what I thought to be the appropriate amount to provide sufficient lube for the bearings then added a little more...just a little no more than that...Quantity wise I'd say around a teaspoon full for each bearing and that's being generous...
iafilius:
--- Quote from: John Rudd on January 21, 2012, 11:56:46 AM ---<snip>
As the spacers were made of plastic, in true Madmodder spirit, new ones just had to be made from metal :coffee:
<snip>
--- End quote ---
Hi John,
bit late to respond to this thread, but just got my Super C3.
preparing to upgrade to tapered barings myself, and having no second lathe this topic got my interest.
I've machined a nylon spacer as a first run on the lathe, which is now 27mm in diameter on the inside, and 40mm in diameter on the outside (which i could measure without disassemble the lathe) . Depth .. i hope long/deep enough, as i don't know the depth yet.
Does anyone know the exact dimensions of the old spacer? and key-depth/with? in order to prepare the spacer as a preparation on front?
But the real reason i respond to this thread, is that i think a metal spacer isn't the best idea to my opinion. I think it is better to have some more elastic spacer, which is able absorb temperature triggered variations, and acts like a spring for manual adjustments as well. Even more when it gets too hot it may act like a fuse.
So i really think some "soft" plastic is better then all metal spacers in this case. I can't particular recommend nylon for this, as the nylon was some kind of a task to machine, and to hold in the chuck.
What do you think of this thought?
Arjan Filius
John Rudd:
Arjan,
I'll post up the dimensions of the orig spacer......
Not sure I agree with the plastic spacer you suggest and the reasoning....properly adjusted the bearings should be fine....if the temperature rises as you suggest, this would affect the bearing preload using a plastic/non-metallic spacer more than the alloy ones I used.....(plastic softening?)
I'm no metallurgists, so let's discuss.....always willing to learn and exchange views
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